Terma 43D Element

What is a heating element?

• A heating element is used as the heat source in an electric towel rail or radiator.
• It works by heating the water or oil inside the radiator, in the same way an element heats water inside a kettle.
• We have a full guide on heating elements if you want to learn even more — click here to read the dedicated guide.

Temperature control & operation

• The Terma 43D Element is pre-programmed to run at an internal temperature of 43 °C, providing Low Surface Temperature (LST) style operation.
• Designed for sensitive environments, ideal for hospitals, care homes, nurseries, and other areas where user safety is critical.
• To ensure correct surface temperature, it is advised to reduce the output of your radiator (as water) by 40% when specifying this element (e.g., for a 200 W towel rail, install a 120 W element).
• No built-in timer, but compatible with an external timer as it remembers settings when switched off.
• Includes a 2-hour drying function for towels or laundry.
• Supplied with a 565 mm internal probe length.
• 66 mm length measured from the thread down, with a 55 mm diameter clock-style face.

Element specifics

• Straight cable supplied, no plug.
• IPx5 rated, suitable for use in bathroom environments.
• Class 1 electrical rating.

Wattage selection advice

• Choosing the correct wattage heating element is essential for safe and effective performance.
• As listed above already - but once again as this is unique to 43D: To ensure correct surface temperature, it is advised to reduce the output of your radiator (as water) by 40% when specifying this element (e.g., for a 200 W towel rail, install a 120 W element).
• Select an element with a wattage as close as possible to the radiator’s central heating (hydronic) output measured in watts.
• If the output is listed only in BTUs, convert using the formula: BTUs ÷ 3.41 = Watts.

Installation

• Full installation instructions are supplied in the accompanying manual, but the following points are useful to read in advance.
• The element must never be switched on in open air — it must be fully submerged in the heating medium to operate safely. Although fitted with safety protection, your tradesman should not power the element on to test it prior to installation.
• The supplied cable is 1.5 metres long and may be shortened or extended (daisy-chained only) as required.
• Heating elements that have been fitted cannot be accepted for change-of-mind returns.
• When installing the element, always use a spanner on the metal neck. Do not apply force to the plastic head, as this may cause cracking or damage.

Electrification advice

• Before electrifying any towel rail or radiator, confirm with the manufacturer that the model is suitable for use with a heating element.
• Not all towel rails or radiators are compatible, as internal design and heat circulation vary between models.
• Installing an element into an unsuitable radiator may lead to poor performance or failure, which would not be a fault of the element.

Dual Fuel advice

• When using this element as part of a dual fuel installation (electric in summer, central heating in winter), the towel rail should be bled regularly.
• Air can gradually build up inside the system, which may cause overheating if the element operates without sufficient water circulation.
• A heating element must never be operated dry, as this can cause excessive surface temperatures and damage towels or clothing.
• This works on the same principle as a kettle — never run it without water inside.

• Backed by a 2-year manufacturer’s warranty.
• The typical lifespan of a heating element is between 4 and 7 years, depending on usage.
• At end of life, the 43D heating element can be fully unscrewed and replaced as a single complete unit.

Terma 43D Element Instructions